Toughened aluminum alloy and preparation method thereof

Abstract

The invention provides a strengthened and toughened aluminum alloy and a preparation method thereof.The preparation method comprises the following steps that S1, an aluminum alloy base material is heated to be molten, yttrium modified silicon carbide nanoparticles and nanometer spiral carbon fibers are added, and an electric mechanical stirrer is adopted for stirring; and S2, casting into a mold. The yttrium-modified silicon carbide nanoparticles are adopted, after the yttrium element is introduced, the agglomeration size of the silicon carbide nanoparticles is reduced, a protective film is formed on the surfaces of the silicon carbide nanoparticles, the wettability between the silicon carbide nanoparticles and alpha-Al crystal grains is improved, and the corrosion resistance of the silicon carbide nanoparticles is improved. The tendency of agglomeration of the silicon carbide nanoparticles due to strong molecular action is reduced, and the silicon carbide nanoparticles can be more uniformly dispersed in an aluminum alloy matrix, so that grain refinement is promoted, and the silicon carbide nanoparticles react with the aluminum alloy matrix to form a yttrium-containing precipitated phase; the phases are dispersed and distributed in a matrix, so that the toughness of the aluminum alloy is obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloy materials, and in particular to a strengthened and toughened aluminum alloy and a preparation method thereof. Background Art

[0002] As a widely used engineering material, aluminum alloy has excellent properties such as light weight, high specific strength and easy recycling. It is particularly important in industries such as shipbuilding, aviation, automobiles, electricity, and construction, and has become one of the important pillar materials for the development of the national economy. In recent decades, aluminum alloys have developed roughly in two directions: one is to develop new high-strength and high-toughness aluminum alloy materials to meet the needs of aviation and aerospace; the other is to develop a series of civilian aluminum alloy materials that can meet various usage conditions. High-strength and high-toughness aluminum alloys mainly include 2××× and 7××× series IM traditional molten aluminum alloys, as well as PM powder metallurgy aluminum alloys, SF injection molding aluminum alloys, aluminum-based composite materials, superplastic aluminum alloys, etc. developed on their basis. In the development of toughened aluminum alloys, by adding suitable fillers, such as ceramic particles, the strength and hardness can be effectively improved, but its toughness will be affected. How to improve the toughness of aluminum alloys on the basis of increasing the strength by modifying the fillers is a problem that this patent needs to solve. Summary of the invention

[0003] Technical problems to be solved: In view of the above technical problems, the purpose of the present invention is to provide a toughened aluminum alloy and a preparation method thereof, wherein yttrium-modified silicon carbide nanoparticles are used. After the yttrium element is introduced, the agglomeration size of the silicon carbide nanoparticles is reduced, and a "protective film" is formed on the surface of the silicon carbide nanoparticles, which improves the wettability between the silicon carbide nanoparticles and the α-Al grains, reduces the tendency of the silicon carbide nanoparticles to agglomerate due to their strong molecular interaction, and enables the silicon carbide nanoparticles to be more evenly dispersed in the aluminum alloy matrix, thereby promoting grain refinement, and reacting with the aluminum alloy matrix to form yttrium-containing precipitated phases, which are dispersed in the matrix and have a significant improvement effect on the toughness of the aluminum alloy. In addition, yttrium and the aluminum alloy matrix can form Al3Y hard phases, which serve as heterogeneous nucleation points in the aluminum alloy, increase the nucleation rate of α-Al, thereby refining the grains and improving the mechanical properties of the aluminum alloy.

[0004] Technical solution: A method for preparing a toughened aluminum alloy, comprising the following steps: S1: heating the aluminum alloy substrate until it is melted, adding yttrium-modified silicon carbide nanoparticles and nano-helical carbon fibers, and stirring with an electric mechanical stirrer; S2: Cast into a mold. Furthermore, the aluminum alloy substrate is composed of the following components: Zn: 7.6-8.4%, Mg: 1.8-2.3%, Cu: 2.0-2.6%, and the balance is Al. Furthermore, the particle size of the yttrium-modified silicon carbide is 50-300 nm. Furthermore, the helical diameter of the nano-helical carbon fiber is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm. Furthermore, the mass ratio of the aluminum alloy to the yttrium-modified silicon carbide nanoparticles is 100:(10-18); the mass ratio of the yttrium-modified silicon carbide nanoparticles to the nano-helical carbon fibers is (2-3):1. Furthermore, the preparation method of the yttrium-modified silicon carbide nanoparticles is: (1) Mix 50-60 parts of metallic silicon powder, 40-50 parts of wheat husk powder and 0.1-1 parts of yttrium powder, and place in a ball mill for 20-24 hours; (2) After taking out, add 3-5 parts of carboxymethyl cellulose and 10-20 parts of water, continue stirring for 6-10 hours, and obtain a slurry; (3) placing the slurry in a vacuum pressure tank, injecting the slurry into a mold after vacuum treatment, opening the mold after 8-12 hours, and placing it in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace, heating it to 600-700° C. and keeping it for 1-2 hours, then heating it to 1350-1400° C. and keeping it for 2-4 hours, and cooling it to room temperature in the furnace to obtain yttrium-modified silicon carbide nanoparticles. Furthermore, in the step (1), the ball milling speed is 300-400 rpm. Furthermore, the vacuum treatment conditions in step (3) are: vacuum degree 2.5-9 KPa; vacuum treatment time 1-2 h. Furthermore, the vacuum degree of the vacuum furnace in step (4) is ≥2Pa. The strengthened and toughened aluminum alloy prepared by the above method. Beneficial effects: 1. The present invention adopts a composite filler of yttrium-modified silicon carbide nanoparticles and nano-helical carbon fibers. The yttrium-modified silicon carbide nanoparticles are a "point" structure, and the nano-helical carbon fibers have both a two-dimensional line structure and a three-dimensional structure. The two can further form a more complex network structure to enhance the mechanical properties of the aluminum alloy. 2. The present invention adopts yttrium to modify silicon carbide nanoparticles. After the introduction of yttrium, the agglomeration size of silicon carbide nanoparticles is reduced, and a "protective film" is formed on the surface of silicon carbide nanoparticles, which improves the wettability between silicon carbide nanoparticles and α-Al grains, reduces the tendency of silicon carbide nanoparticles to agglomerate due to their strong molecular interaction, and can make silicon carbide nanoparticles more uniformly dispersed in the aluminum alloy matrix, thereby promoting grain refinement, and reacting with the aluminum alloy matrix to form yttrium-containing precipitated phases. Such phases are dispersed in the matrix and have a significant improvement effect on the toughness of the aluminum alloy. In addition, yttrium and the aluminum alloy matrix can form Al3Y hard phases, which serve as heterogeneous nucleation points in the aluminum alloy, increase the nucleation rate of α-Al, thereby refining the grains and improving the mechanical properties of the aluminum alloy. 3. The present invention uses nano-scale silicon carbide particles, which have strong interface bonding force and can significantly refine primary α-Al dendrites, which helps to break the strength-ductility trade-off and obtain a strengthened and toughened aluminum alloy. DETAILED DESCRIPTION The present invention proposes a toughened aluminum alloy and a preparation method thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention will be further described in detail with reference to the embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The aluminum alloy substrate used in the following examples consists of the following components: Zn: 8.0%, Mg: 2.2%, Cu: 2.4%, and the balance is Al. Example 1 A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 50 parts of metallic silicon powder, 45 parts of wheat husk powder and 0.7 parts of yttrium powder, place them in a ball mill and mill them for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 15 parts of yttrium-modified silicon carbide nanoparticles and 5 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour the mixture into a mold. Example 2 A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 55 parts of metallic silicon powder, 45 parts of wheat husk powder and 0.7 parts of yttrium powder, place them in a ball mill and mill them for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 15 parts of yttrium-modified silicon carbide nanoparticles and 5 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour the mixture into a mold. Example 3 A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 60 parts of metallic silicon powder, 45 parts of wheat husk powder and 0.7 parts of yttrium powder, place in a ball mill and mill for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 15 parts of yttrium-modified silicon carbide nanoparticles and 5 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour the mixture into a mold. Example 4 A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 55 parts of metallic silicon powder, 45 parts of wheat husk powder and 0.1 parts of yttrium powder, place them in a ball mill and mill them for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 15 parts of yttrium-modified silicon carbide nanoparticles and 5 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour into a mold. Example 5 A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 55 parts of metallic silicon powder, 45 parts of wheat husk powder and 0.4 parts of yttrium powder, place in a ball mill and mill for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 15 parts of yttrium-modified silicon carbide nanoparticles and 5 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour the mixture into a mold. Example 6 A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 55 parts of metallic silicon powder, 45 parts of wheat husk powder and 1.0 part of yttrium powder, place in a ball mill and mill for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 15 parts of yttrium-modified silicon carbide nanoparticles and 5 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour the mixture into a mold. Example 7 A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 55 parts of metallic silicon powder, 45 parts of wheat husk powder and 0.7 parts of yttrium powder, place them in a ball mill and mill them for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 10 parts of yttrium-modified silicon carbide nanoparticles and 3.33 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour the mixture into a mold. Example 8 A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 55 parts of metallic silicon powder, 45 parts of wheat husk powder and 0.7 parts of yttrium powder, place them in a ball mill and mill them for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 18 parts of yttrium-modified silicon carbide nanoparticles and 6 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour the mixture into a mold. Example 9 A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 55 parts of metallic silicon powder, 45 parts of wheat husk powder and 0.7 parts of yttrium powder, place them in a ball mill and mill them for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 15 parts of yttrium-modified silicon carbide nanoparticles and 7.5 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour the mixture into a mold. Comparative Example 1 The difference between this embodiment and embodiment 2 is that yttrium powder is not added. Specifically: A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 55 parts of metallic silicon powder and 45 parts of wheat husk powder, place them in a ball mill and mill them for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 15 parts of yttrium-modified silicon carbide nanoparticles and 5 parts of nano-helical carbon fibers, wherein the helical diameter of the nano-helical carbon fibers is 0.3-1 μm, the fiber diameter is 40-60 nm, and the helical pitch is 80 nm, and stirring is performed using an electric mechanical stirrer; (6) Pour the mixture into a mold. Comparative Example 2 The difference between this embodiment and embodiment 2 is that no nano helical carbon fibers are added, and all yttrium-modified silicon carbide nanoparticles are added. Specifically: A method for preparing a toughened aluminum alloy comprises the following steps: (1) Mix 55 parts of metallic silicon powder, 45 parts of wheat husk powder and 0.7 parts of yttrium powder, place them in a ball mill and mill them for 24 hours at a speed of 350 rpm; (2) After taking out, add 5 parts of carboxymethyl cellulose and 20 parts of water, continue stirring for 10 hours to obtain a slurry; (3) The slurry is placed in a vacuum pressure tank, and after vacuum treatment for 2 hours, the slurry is injected into a mold with a vacuum degree of 2.5 KPa. After 12 hours, the mold is opened and placed in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace with a vacuum degree of 2 Pa, heating to 650° C. and keeping the temperature for 2 h, then heating to 1400° C. and keeping the temperature for 4 h, and cooling the green body to room temperature to obtain yttrium-modified silicon carbide nanoparticles with a particle size of 50-300 nm; (5) heating 100 parts of an aluminum alloy substrate until it is melted, adding 20 parts of yttrium-modified silicon carbide nanoparticles, and stirring with an electric mechanical stirrer; (6) Pour the mixture into a mold. The mechanical properties of each embodiment were tested according to the national standard method, and the results are shown in Table 1 below: Table 1

Claims

1. A method for preparing a toughened aluminum alloy, characterized in that: The following steps are involved: S1: heating the aluminum alloy substrate until it is melted, adding yttrium-modified silicon carbide nanoparticles and nano-helical carbon fibers, and stirring with an electric mechanical stirrer; S2: Cast into a mold.

2. The method for preparing a toughened aluminum alloy according to claim 1, characterized in that: The aluminum alloy substrate consists of the following components: Zn: 7.6-8.4%, Mg: 1.8-2.3%, Cu: 2.0-2.6%, and the balance is Al.

3. The method for preparing a toughened aluminum alloy according to claim 1, characterized in that: The particle size of the yttrium-modified silicon carbide nanoparticles is 50-300 nm.

4. The method for preparing a toughened aluminum alloy according to claim 1, characterized in that: The nano-helical carbon fiber has a helical diameter of 0.3-1 μm, a fiber diameter of 40-60 nm, and a helical pitch of 80 nm.

5. The method for preparing a toughened aluminum alloy according to claim 1, characterized in that: The mass ratio of the aluminum alloy to the yttrium-modified silicon carbide nanoparticles is 100:(10-18); the mass ratio of the yttrium-modified silicon carbide nanoparticles to the nano-helical carbon fibers is (2-3):

1.

6. The method for preparing a toughened aluminum alloy according to claim 1, characterized in that: The preparation method of the yttrium-modified silicon carbide nanoparticles is: (1) Mix 50-60 parts of metallic silicon powder, 40-50 parts of wheat husk powder and 0.1-1 parts of yttrium powder, and place them in a ball mill for 20-24 hours; (2) After taking out, add 3-5 parts of carboxymethyl cellulose and 10-20 parts of water, and continue stirring for 6-10 hours to obtain a slurry; (3) placing the slurry in a vacuum pressure tank, injecting the slurry into a mold after vacuum treatment, opening the mold after 8-12 hours, and placing it in an oven for drying to obtain a green body; (4) placing the green body in a vacuum furnace, heating it to 600-700° C. and keeping it for 1-2 hours, then heating it to 1350-1400° C. and keeping it for 2-4 hours, and cooling it to room temperature in the furnace to obtain yttrium-modified silicon carbide nanoparticles.

7. The method for preparing a toughened aluminum alloy according to claim 6, characterized in that: The ball milling speed in the step (1) is 300-400 rpm.

8. The method for preparing a toughened aluminum alloy according to claim 6, characterized in that: The vacuum treatment conditions in step (3) are: vacuum degree 2.5-9 KPa; vacuum treatment time 1-2 h.

9. The method for preparing a toughened aluminum alloy according to claim 6, characterized in that: The vacuum degree of the vacuum furnace in the step (4) is ≥2Pa.

10. A toughened aluminum alloy prepared by the method according to any one of claims 1 to 9.

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